Rotary casting



0. 3. DE LAVAUD.

ROTARY CASTING.

APPLICATION FILED HOV. 27,1918.

Patented Feb. 3,1920.

INVENTOR.

A TTORNEYS.

UNITED STATES PATENT OFFICE.

JDIMITBI SEINSAUD DI LAVAUD, OI NEW YORK, N. Y;

ROTARY CASTING.

To all whom it may concern:

Be it known that I, DIMITRI SENSAUD on I uxum, a citizen of the United States of Brazil, and a resident of New York, in the county of New York and State of New York, have invented certain new and useful Improx'ements in Rotary Casting, of which the following is a specification.

. This invention relates to rotary casting,

and provides an improved method of casting metallic bodies and improved apparatus for carrying out such method, particularly having to do with the rotary mold and the supporting, driving, and fluid-cooling means therefor.

\Vhile the new mold may be water-cooled, no special ball-bearings are required for mounting the same. Despite the absence of ball-bearmgs, no jamming of the mold relative to the supports on which it is rotatively mounted may occur. Other advantages will hereinafter appear, of equal, if not greater importance than those mentioned; a para- .mount advantage being that surface pits and cavities on the outside of the pipe, due to the'trapping of the gases generated during congealing of the casting, and heretofore encountered and a very serious defect especially in pipes, ofsix inch diameter and smaller, are entirely eliminated.

For more than one hundred years attempts have been made to make metallic castings by means of a rotary mold, generally by employing centrifugal force to spread uniformly over the interior of the rotary mold the molten metal variously delivered to the interior of the mold. These castings have obviouslybeen of an annular type, either tubular or of substantially areshaped cross-section. Because the metal mold has been of a one-piece construction,

or at least formed of rigidly joined sections, 1

the lengths of which sections have been at least as long as, and generally much longer, than their diameters, commercial casting by means of using these molds was not possible, so far as I am aware, until more or less complicated arrangements were evolved and employed, such as disclosed in my copend-.

ing United States applications, Serial Nos. 194,976 and 194,977. The first of these applications discloses a method of and means for evenly cooling a rotary mold from end to end thereof by means of a water jacket as long as the mold and sleeving the mold from end to end, with the water jacket hav- Specification of Letters Patent.

ing its outlet of a cross-sectional area less than that of its inlet. .In other words, the

essence of that invention was the provision of an annular water jacket havin a conwater in the jacket, this was not enough, as

I found that there was one part of the mold which was hotter than any other. i This was the line arallel to the axis of the mold, along whlch the metal was first poured. At

' the instant the metal was poured, steam formed on the outside of the mold, opposite the line along which the poured metal'first hit the inside of the mold; and the adherence of the water to the mold, as this expression may be used for want of abetter-one,

was not absolute, but relative, thatis, was not uniform. I found that the cause of this Patented Feb. 3,1920. Application filed November 27, 1918. Serial No. 264,444.

.tinuous flow, of water therethroug under was that as soon as this one line of the mold was thus suddenly highl heated a certain quantity of steam forme itself between the outside of the mold and the water. I found,

further, that unless this steam formation was suppressed so promptly and adequately that in efi'ect it never really commenced, serious difiiculties arose. If the steam formation occurred along a particular portion of the mold, thus preventing the mold from being completely surrounded by water at every point, the mold contracted and expanded at difierent portions and fatal distortion took place. In experiments in Brazil, made four or five years ago,'I discovered further, thatwhere the mold was attempted to be supported and rotated upon a plurality of rollers below the moldsince any at:- tempt to mount the rigid mold, ,then, and until now deemed essential, upon ball-bearings, as then known, was impracticable, due to the jamming of the mold in a very short time following the attainment by, the mold of a temperature greatly in excess of the temperature of the journaling' supports.

along the line of the mold where the molten metal was first delivered, and manifested itself as an arching of the mold wall along this line toward t e mold axis. This distortion of the mold and the consequent vibration and rattling of the mold on the rollers was so serious that in practically all cases the mold was destroyed, by bursting apart at its middle, after the casting of no more than one hundred pipes. To overcome this difficulty, I devised the ball-bearing disclosed in my copending United States application, Serial No. 194,977, the feature of this ball-bearing 'being a mounting of the inner race of the ball-bearing on the j ournaling support and the mounting of the outer race on the mold, to defeat jamming due to transverse expansion in the mold, and the provision between the two races of ballpockets elongated axially to the mold, to defeat jamming of the mold due to longitudinal expansion of the mold. Thereafter, by

the use in particular of the water cooling of Y the mold under pressure and of the ballbearings just described, the commercial and rapid manufacture of metal pipes and the like by the centrifugal method was at tained; but subject to certain objections, among others as follows: (a) the costliness of interchanging molds of different internal diameters in the casting machine due to the necessity of providing the familiar ringshaped members to close the ends of the water jacket and to join the ends of the mold to the outer races of the ball-bearings, and (b) the necessity ofscrapping an entire mold or a majb'r part thereof upon damaging any part of the mold as the result of premature deposits of molten metal therein or otherwise.

The present invention overcomes the previous disadvantages just noted, and, as

,above stated, eliminates the necessity for water cooling the mold under pressure and of mounting the mold on ball-bearings, and involves the method of casting a single metallic body'by providing a rotary multipart mold, securing the mold parts together to maintain them in predetermined juxtaposition to permit the mold to be rotated about an axis, with all the mold parts moving as substantially one unit, at the same time maintaining the mold parts in slightly loose relation, and delivering molten metal to the mold during rotation. By slightly loose relation is meant that the mold parts are not clamped together so tightly as to prevent expansion of some or all of the parts, evenly or unevenly, without destroying the continuity and smoothness of the designed inner and outer circumferential surfaces of the mold, but tightly enough to prevent the molten metal delivered to the mold from entering the interstices between contiguous mold parts. Preferably the lamellar components of ring form, arranged in face to face relation about a common axis, so that the mold is build up longitudinally by the multiplicity of components arranged n planes transverse to the mold. In carrying out such process, there is provided what may be termed a flexible mold, that is, a mold which, while having a great number of components capable of dissimilar expansions, maybe merely depositing on a plurality of supporting and underlying driving rollers with the assurance that the longitudinal contour of the mold will always automatically adapt itself to lie closely upon the peripheries of the rollers. The mold being preferably constructed, as stated, of a multiplicity of lamellar components, these components are preferably very thin, that is, of very small face relative to diameter. It would be desirable, I now believe, to have such face not more than one-sixteenth of an inch where the internal diameter of the component is appropriate to the making of four, five and six-inch pipe or more.

In the same way that the new mold con struction permits the elimination of ballbearings and the utilization of supporting rollers for the mold, the new mold obviates any necessity for water-cooling the mold under pressure. I have found that when the parts of the mold are clampedto gether with the degree of tightness specified, the spaces between the mold parts at all times are such that when the rotating mold is partially submerged in a collection of cooling fluid, as water, the mold is adequately and uniformly cooled from end to end due to the seepage of fluid into the interstices between the mold parts. Preferably, the degree of submergence of the mold in the collection of cooling fluid is not such as to bring the'lowermost point of the mold interior below the fluid level, since otherwise -the cooling fluid might enter the mold intenor and prevent flawless casting. Accord- Therefore. the invention in another aspect may be said to reside intheprovision of a method of rotary casting which consists in providing a mold having gas-escape openings, delivering molten metal to the interior of the mold. rotating the mold. and fluid cooling successive circumferential subdivisions of the mold while exposing to the atmosphere gas-escape openingsin other circumferential subdivisions of the mold, By the expression gas-escape openings is not necessarily meant the gas-escape openings ofiered by the interstices between a multiplicity of very thin mold parts, as it may be that these openings may in practice be found to be otherwise established or constituted.

The invention will be more clearly understood from the following description, when taken in connection with the accompanying drawings illustrating an embodiment, at present preferred, of which drawings Figure 1 is an axial sectional view of an apparatus adapted to carry out the process;

Fig. 2 is an end elevation of the parts shown in Fig. 1, showing also mounting means for the mold to render the same slidable longitudinally; and

' Fig. 3 is a transverse section taken on the line 33 of Fig. 1.

The mold a is supported upon a pair of parallel rollers 5, journaled at their opposite ends in the end walls of a receptacle 6.

The mold is comprised of a plurality of lamellar components, as indicated in Fig. 1 (where the components are not cross-hatched to indicate their sections, in view of the scale of the drawing), one of which components is shown clearly in Fig. 3 at 7. The

mold may be comprised of a plurality of duplicate ring-shaped lamellar components, as shown in the drawing. In the present case, the mold 4 comprises, in addition to the pluralities of duplicate ring-shaped lamellar components at both sides of a detent-ring 8, as shown in Fig. 1, pluralities of lamellar components of difi'erent sizes, as indicated at 9 in Fig. 1, to permit the casting of belled pipe.

The detent-ring 8 is provided for coactionwith suitable grooves in the rollers 5, one of which grooves is shown at 10. Fig. 1, and serves to prevent longitudinal shifting of the mold as a unit relative to the supporting rollers 5.

On the assumption that the metal delivering trough (familiar in the art, but not shown) and the mold are to be placed in overlapping relation by entrance of' the trough into the mold at the left end of the construction of Fig. 1, the left end of the mold is formed of a shaped ring 11, so formed as to hold within the mold the molten metal delivered thereto and being spread therein by the -molds rotation. At the other end of the mold any suitable device, such as the removable end plate, familiar in the art, (see U. S. Patent No.

1,276,038 issued to me) may be employed either for making belled or straight pipe.

The various components 7, 8, 9, and 11 of the mold, as above described, are secured together according to the invention by means of longitudinal tie-rods 12 passed through apertures in the components and suitably headed at opposite ends, as indicated.

The mold 4, being flexible as described, being supported from end to end on the rollers-5, and being formed of lamellar components, each of which may be machined with a degree of precision unattainable in the machining of a one-piece mold, provides such a truly cylindrical and unbroken interior surface, and one so absolutely coaxial with the rollers 5, that the casting of pipe having uniform wall thicknesses and the easy withdrawal of such pipe after congealing, things which heretofore have not been entirely dependable features, may always be counted on.

These components are most advantageously stamped out of sheet metal, say Bessemer steel, of thin gage. In this connection, it should be pointed out that the waste of metal is practically nothing, since scoping another inlet conduit 15 leading from a source-of water supply. The collection 13 is maintained at the desirable level indicated in Fig. 3 by means of a vertical drain pipe 16 opening into an outlet conduit 1 secured to the receptacle and telescoping another conduit (not shown) leading to a suitable point of discharge. When during casting, the mold 4 is rotated, partially submerged in the collection 13, great facility in cooling the mold is afforded, due to the seepage of the water between the lamellar components and the simultaneous escape of the generated gases through the interstices between the components at points above the water level. This cooling action is further increased by the rotation under water of the supporting rollers 5, coincident with the rotation of the mold, since one at least of these rollers, irrespective of the direction of the rotation of the mold, always sets up water currents in the collection 13 tending to drive the water toward and between the components 7 with some force, resulting in further efiiciency in suppressing steam formation where it would otherwise occur, that is, between the components Where they are submerged. Indeed, the cooling eiiic'iency of the arrangement now being described is so great that Whereas heretofore R. P. M. for 6" pipes even for iron castings,

now the mold need only be rotated at approximately. 600 R. P. M.

The mold is rotated through employing one of the. rollers 5 as a driving roller, this roller 5 being in turn driven by an electric motor 18 mounted upon'a bracket at one side of the receptacle 6; the motor shaft having fixed thereon a pinion 19, the roller 5 just referred to having fixed thereon a gear 20, and the gear and pinion belng coupled by a link-belt or the like, as 1nd1- cated at 21 in Fig. 2.

It will be observed that due to the telescoped inlet and outlet conduits for the receptacle, as above described, and the mounting on the receptacle of the complete power plant for rotating the mold 4:, the present invention may advantageously but not necessarily be used as a feature of the invention disclosed in United States Patent Number 1,276,038, issued to me, according to which, preparatory to casting, the mold and not the trough is moved longitudinally to bring the mold and trough into overlapping relation.- And to this end the receptacle 6 carries a plurality of wheels 22, adapted to travel on rails 23 fixed to a suitable base 24.

Packing, as indicated at 25, may be provided to prevent exit of the liquid 13 .from the receptacle -6 other than by way of the drain pipe 16.

Since the filing of this application it has been discovered that the rolling action of one of the rollers 5, relative to the collection of cooling liquid 13, has a very high degree of cooling efliciency relative to the subdivisions of the mold subjected to such cooling fluid; indeed, such a high degree of 'cooling etliciency as to permit the use of a solid mold, rather thana laminated one, for practical operation, with such mold journaled and supported merely by resting on two rollers similar to the rollers 5 during rotation of the mold. It has also been dis covered that in the case of such a solid mold, and in the case of a laminated mold struc ture according to the above disclosure, but when both molds are journaled and supported merely by resting on two rollers similar to the rollers 5, the cooling fluid may be applied otherwise than by successively submerging diflercnt circumferential subdivisions of'the mold in the fluid 13 during rotation of the mold, provided arrangements are made for applying a cooling fluid to such subdivisions of the moldprefe-rably to such subdivisions as they lie near the under side of the mold and between the rollers 5 and such fluid application is made under a. certain pressure somewhat equivalent to the pressure set up against the mold exterior by the fluid in collection 13 resulting from the rolling action of one of the rollers 5 just referred to. For example, a cooling fluid could be injected or sprayed, preferably tangentially, toward successive circumferential subdivisions of the outside of the mold as such subdivisions lie between the rollers 5 during rotation of the mold. Accordingly, the right is reserved to file another application, vin part continuation of this application, and which continuation application will be filed of even date herewith, covering the invention embodied in the means devised to carry out these latter discoveries. Such continuation application will'then be a continuation in part of the present application, in that part of the former will constitute a division of this application so far as claiming the rolling action set up by one or both of the rollers 5 as just mentioned. In this said continuation application to be filed, the various discoveries stated in this paragraph, and certain others in relation thereto, will be fully disclosed and claimed.

I claim:

1. The method of casting a single metallic body in a rotary multiart mold, which in? cludes securing the mo d parts together to maintain the mold parts in predetermined juxtaposition to permit the mold to be rotated about an axis with all the mold parts moving substantially as one unit, at the same time maintaining the mold parts in slightly loose relation during rotation of the mold, and delivering molten metal to the mold during rotation.

2. The method of casting a single metallic body, which includes providing a multiplicity' of lamellar components of ring form, arranging the components in face to face relation about a common axis, rotating the components simultaneously aboutsuch axis while maintaining the components in slightly loose relation, and delivering molten metal to the interiors of the components.

3. The method of casting a single metallic body, which includes providing a multiplicity of lamellar components ofring form, arranging the components. in face to face relation about a common axis, rotating the components simultaneously about such axis and with the components partially submerged in a cooling fluid while maintaining the components in slightly loose relation, and delivering molten metal to the interiors of the components.

4. The method of casting a single metallic body, which includes providing a multiplicity of lamellar components of ring form, arranging the components in face to face relation about a common axis, rotating the components simultaneously about such axis and with the components partially submerged in a cooling fluid while maintaining the components in slightly loose relation, agitating the fluid to set up currents therein directed toward the interstices betweenthe submerged parts of the components, and delivering molten metal to the interiors of the components.

5. In a rotary casting machine a mold comprising a plurality of ring-shaped, very thin, similar lamellar components, each of one-piece integral construction, arranged multaneously.

6. A casting -machine as described in claim 5,, wherein the holding means are tieelements running longitudinally of the mold and engaging the lamellar components to prevent any but very minute relative move ments of the components.

7. A casting machine as described in claim 6, wherein the components are apertured and the tie-elements are rods passed through such apertures.

8. A casting machine as described in claim 5, wherein the rotating means comprises a plurality of rollers, engaging and supporting the components at their outer peripheries.

9. A casting machine as described in claim 5, wherein means are provided for applying cooling fluid to the interstices between the components as the mold rotates.

10. A casting machine as described in claim 5, wherein there are also provided a cooling-fluid receptacle surrounding the lower part of the mold, a fluid inlet for the receptacle and a fluid outlet for the receptacle, the parts being so designed and arranged as to maintain a fluid level in the receptacle within which the lower part of the mold is always submerged.-

11. A casting machine as described in claim 8, wherein there are also provided a cooling-fluid receptacle below the rollers and the mold, a fluid inlet for the receptacle, and a fluid outlet for the receptacle, the

.parts being so designed and arranged as to maintain a fluid level in the receptacle within which the lower part of the mold is alway submerged.

12. A casting machine as described in claim 9, wherein such means includes fluid confining and guiding means whereby as the mold rotates, successive clrcumferential sections of the components are submerged in the liquid but to an extent insuflicient to bring an interior surface of a component below the fluid level.

13. In a casting machine, a mold built up longitudinally of a series of lamellar components arranged face to face, each component of one-piece integral construction and having a circular outer periphery, the eX- ternal diameter of all components being substantially the same, and means for securing the components together but in such relation as to permit slight lateral distortions of the mold.

14. In a casting machine, a mold inc1uding a series of lamellar components arranged face to face, each component of one-- piece integral construction and having a circular outer periphery, the external diameter of all components being substantially the same, and means for holding the components together in slightly loose relation while restraining the components against greater relative movement than required for uneven expansion of the components.

15. A casting machine as described in claim 14, wherein a pair of rollers are provided for supporting and rotating the mold.

16. In a casting machine, a mold built up of a plurality of lamellar components, means for rotating the mold, and means for delivering cooling fluid against a circumferential subdivision of the mold only, whereby during casting the mold is fluid-cooled and at the same time is open -to the'atmosphere by way of the interstices between the components to permit free escape of the gases. 

